- Email: [email protected]
05419 Focus on chillers
73
Space heating and cooling Experlmental
SSlQSSl 5
number and temperature
relatlonshlps
difference
for
heat
Nusselt
flux,
In a finned heater
Karabacak, R. Energy Cowers. Mgmt., May 1996, 37, (S), 591-597. In this study, a heater with finned surface, having a large application field in practice and working in accordance with the principle of natural convection heat transfer, is investigated. In such systems, the increase of heat transfer coefficient is obtained by preventing the rise of the thickness of the thermal layer using an obstacle on the heater surface and fins for widening the total surface. The temperature difference between the body-environment, and the heat transfer coefficients obtained from the heater change, depend on the fin parameters and heat flow applied on the system. In cylindrical heaters with circular fins and horizontal location, the vertical fluid flow on the side fin towards the outer surface increases the performance of the heater sufficiently.
Expert system to determine energy-saving potential of public bulldlngs Gatton, T. M. er al., ASHRAE Trans., 1995, 101, (21, 163-171.
96106416
retrofit
The paper discusses the research effort being made in.the development of an expert system for energy use evaluation of buildings. Examines the particular characteristics of the predetermination of energy inefficient buildings and costs effective energy retrofit alternatives and how they may be solved by the use of an expert system.
96105417 perature constant
and
Finite-difference prediction of transient indoor related correlation based on the building
temtime
Inr. J. Energy Research, Jun. Antonopoulos, K. A. and Tzivanidis, C. 1996. 20. (61. 507-520. A numehc‘al’procedure for the calculation of the transient indoor temperature in buildings is developed. THe procedure is based on an implicit finite-difference solution of a closed set of differential equations, which express the indoor energy balance and the transient heat conduction in all elements of the building envelope. Using the above procedure, calculations are carried out for 21 types of buildings with 18 and 10 different kinds of wall and roof constructions, respectively, i.e. the total number of building cases examined is 21 X 18 X 10 = 3780 with floor areas ranging from 30 m2 to 3000 m’. It is found that buildings of different construction characteristics and sizes but with the same time constant, respond in a similar way under the same outdoor temperature variation.
Flexible and alternative pipe laying systems 96105416 Schwarz, H. Eurohear & Pwr. Fern. Inrernar., Jan.-Feb. 1996, 25, (l), 32-37. (In German) The paper discusses the opportunities for reducing the costs of laying district heating pipes of medium and lower nominal widths. This is necessary if the distr% ‘heating industry wishes lo remain competitive, especially against the gas supply industry. 96105419
Focus
on chillers
96105420
Further
progress
with mlxed
refrigerants
and
for power
saving
Bensafi, A. and Haselden, G. G. Proc. Insr. Refrig., Feb. 1996, l-11. Discusses a report on tests carried out using the original test rig with a R23/R134a blend. States that despite the wide boiling range the unit worked well and gave coefficients of performance between 3.5 and 4.4. 96105421
absorption cooling systems. Part absorber and condenser temperatures Murthy, S. Int. J. Energy Research, Jun. 1996,
HCFCPPebased
Ill: Effects of different Fatouh, M. and Srinivasa
20, (6), 483-494. Generally in a vapour absorption refrigeration system (VARS) heat rejection temperatures at absorber (T,) and condenser (T,) are taken to be equal. However, different temperatures can exist when the cooling water flows in series through the two components. Under such situations, it is essential to know which of T, and T, has greater influence on the performance of the VARS. Here the Influence of different T, and T, on the performance of a single-stage VARS working with HCFC22 as a refrigerant and three organic solvents, namely DMA, DMF And DEMTEG, as absorbents is studied. Results are obtained over a wide range of operating temperatures.
Heat transfer and fluid flow 96105422 Rode, C. and Burch, D. M. Proc. VI Thermal Performance of the Exterior Envelopes of Buildings Con&, ASHRAE, 1995, 283-295. The paper describes a computer program for transient modelling of combined heat and moisture transfer in building constructions. History of sealed refrigeration systems 96105423 Nagengast, B. ASHRAE J., Jan. 1996, 38, (l), S37-38. A history of the development of sealed refrigeration systems since the commencement of a search 100 years ago for a solution to the problem of leaky refrigeration systems.
376
Fuel
and Energy
Abstracts
September
1996
alternatives
to CFC-114
Bare, J. C. ASHRAE J., Jan. 1996, 38, (11. 44-46. Describes research carried out by EPA in‘aisociation with the US navy to find a non-ozone depleting refrigerant for retrofitting the navy’s fleet of 850 shipboard chillers currently using the chlorofluorocarbon R114 as a refrigerant. Describes the findings, which show R236fa or R236ea, as logical replacement candidates for R114.
Improving the efficiency of air conditioning refrigeration Smith. M. H. and Calder. K. Co& ro Examine Cost Effective Solutions. ,, Inst. defrig., 1995, 15 pi. . 96105425
The paper discusses improvements refrigeration.
in the efficiency
of air conditioning
96105426 Indoor air quality and the varlable-alr-volume/bypass filtration system: Chamber experlment Moschandreas, D. J. er al., Environmenf Inr., 1996, 22, (2), 149-158. Two series of experiments were performed in an all aluminum chamber under controlled conditions lo investigate whether the variable-air-volume/bypass filtration system reduces indoor air pollutant concentrations relative to a conventional variable-air-volume. Twelve short-term experiments (100 min) were performed for each ventilation system using indoor sources and one energy load.
The influence of heat-transfer law on the endoCarnot refrigerator Chen, L. er al., J. Iwr. of Energy, Jun. 1996, 69, (479), 96-100. The general performance characteristics of a finite-speed Carnot refrigerator were investigated, and the relationship between the coefficient of per-
96105427
reversible
formance and the cooling load of the refrigerator was obtained for several heat-transfer cases. The results provide a realistic design criterion for actual refrigerators.
96105426 prediction
Measurement and computational fluid dynamics of diffuser pressure-loss coefficient Gan, G. and Riffat, S. B. Applied Enero, Jun. 1996, 54, (2), 181-195. The paper presents measurements and predictions of the pressure-loss coefficient for a wide-angle, three-dimensional diffuser with free discharge. The constant tracer-gis method was used for measuring duct mean vel& ity, and static pressure tappings for pressure change across the diffuser. The effect on the loss coefficient of a bend orecedine the diffuser was investigated for various spacer lengths. Compuiational fluid dynamics predictions were carried out to study flow stabilities in diffusers of different divergence angles.
for improving the operation and energy of HVAC cooling systems Kosonen, R. et al., Finlatrd Technical Research Centre, TRC Research Note 1725, 1996, 82 pp. (In Finnish) 96105429
Murdoch,
M. er al., Refrig. Alr Condit., Feb. 1996, 99, 19-33. Six short articles dealing with aspects of chiller technology applications.
96105424 Identifying and evaluating for navy shlpboard~chillers
Methods
performance
The report presents retrofit concepts primarily addressing the energy efficiency and operation of cooling systems. Considers direct expansion cooling systems, water chillers and room air conditioner packages.
96105430
Moisture
exchange
in rotary
heat
exchangers
Dreher, E. K!‘Lufr. Kalrerech., Jan. 1996, 32, (l), 23-27. (In German) Reports that the achievable heat recovery efficiences of rotary heat recovery units employing a sorptive activated coating, as used in air conditioning systems, are controversial. Discusses a newly designed diagram in which it demonstrates not only the heat balance and moisture balancing taking account of the sorptive material, but also the correlative influence.
96105431 Natural ventilation in atria Andersen, K. T. ASHRAE Trans., Paper NoSD-95-6-4, 1995, 101, (2), 866-874. Discusses how natural ventilation by thermal buoyancy and wind is very suitable for atria, provided the geometry and openings are correctly designed. Presents a set of formulas for determining air velocities, temperature differences and ventilation capacity in relation to openings,
Optimisation functions in building services 96105432 Steinemann, J. Techtrik am Bau, Feb. 1996, (2), 49-52, 69-70. (In German) Describes model calculations for applications in air conditioning and ventilation based on Swiss guidelines.
Optimisation of availability performance in a dissystem Kekkonen, S. Finland Techtrical Research Cenrre, TRC Research Note 1670, 1995, 47pp. (III Finnish) 96105433
trict
heating
Discusses the Finnish
district
heating system.
Space heating and cooling Experlmental
SSlQSSl 5
number and temperature
relatlonshlps
difference
for
heat
Nusselt
flux,
In a finned heater
Karabacak, R. Energy Cowers. Mgmt., May 1996, 37, (S), 591-597. In this study, a heater with finned surface, having a large application field in practice and working in accordance with the principle of natural convection heat transfer, is investigated. In such systems, the increase of heat transfer coefficient is obtained by preventing the rise of the thickness of the thermal layer using an obstacle on the heater surface and fins for widening the total surface. The temperature difference between the body-environment, and the heat transfer coefficients obtained from the heater change, depend on the fin parameters and heat flow applied on the system. In cylindrical heaters with circular fins and horizontal location, the vertical fluid flow on the side fin towards the outer surface increases the performance of the heater sufficiently.
Expert system to determine energy-saving potential of public bulldlngs Gatton, T. M. er al., ASHRAE Trans., 1995, 101, (21, 163-171.
96106416
retrofit
The paper discusses the research effort being made in.the development of an expert system for energy use evaluation of buildings. Examines the particular characteristics of the predetermination of energy inefficient buildings and costs effective energy retrofit alternatives and how they may be solved by the use of an expert system.
96105417 perature constant
and
Finite-difference prediction of transient indoor related correlation based on the building
temtime
Inr. J. Energy Research, Jun. Antonopoulos, K. A. and Tzivanidis, C. 1996. 20. (61. 507-520. A numehc‘al’procedure for the calculation of the transient indoor temperature in buildings is developed. THe procedure is based on an implicit finite-difference solution of a closed set of differential equations, which express the indoor energy balance and the transient heat conduction in all elements of the building envelope. Using the above procedure, calculations are carried out for 21 types of buildings with 18 and 10 different kinds of wall and roof constructions, respectively, i.e. the total number of building cases examined is 21 X 18 X 10 = 3780 with floor areas ranging from 30 m2 to 3000 m’. It is found that buildings of different construction characteristics and sizes but with the same time constant, respond in a similar way under the same outdoor temperature variation.
Flexible and alternative pipe laying systems 96105416 Schwarz, H. Eurohear & Pwr. Fern. Inrernar., Jan.-Feb. 1996, 25, (l), 32-37. (In German) The paper discusses the opportunities for reducing the costs of laying district heating pipes of medium and lower nominal widths. This is necessary if the distr% ‘heating industry wishes lo remain competitive, especially against the gas supply industry. 96105419
Focus
on chillers
96105420
Further
progress
with mlxed
refrigerants
and
for power
saving
Bensafi, A. and Haselden, G. G. Proc. Insr. Refrig., Feb. 1996, l-11. Discusses a report on tests carried out using the original test rig with a R23/R134a blend. States that despite the wide boiling range the unit worked well and gave coefficients of performance between 3.5 and 4.4. 96105421
absorption cooling systems. Part absorber and condenser temperatures Murthy, S. Int. J. Energy Research, Jun. 1996,
HCFCPPebased
Ill: Effects of different Fatouh, M. and Srinivasa
20, (6), 483-494. Generally in a vapour absorption refrigeration system (VARS) heat rejection temperatures at absorber (T,) and condenser (T,) are taken to be equal. However, different temperatures can exist when the cooling water flows in series through the two components. Under such situations, it is essential to know which of T, and T, has greater influence on the performance of the VARS. Here the Influence of different T, and T, on the performance of a single-stage VARS working with HCFC22 as a refrigerant and three organic solvents, namely DMA, DMF And DEMTEG, as absorbents is studied. Results are obtained over a wide range of operating temperatures.
Heat transfer and fluid flow 96105422 Rode, C. and Burch, D. M. Proc. VI Thermal Performance of the Exterior Envelopes of Buildings Con&, ASHRAE, 1995, 283-295. The paper describes a computer program for transient modelling of combined heat and moisture transfer in building constructions. History of sealed refrigeration systems 96105423 Nagengast, B. ASHRAE J., Jan. 1996, 38, (l), S37-38. A history of the development of sealed refrigeration systems since the commencement of a search 100 years ago for a solution to the problem of leaky refrigeration systems.
376
Fuel
and Energy
Abstracts
September
1996
alternatives
to CFC-114
Bare, J. C. ASHRAE J., Jan. 1996, 38, (11. 44-46. Describes research carried out by EPA in‘aisociation with the US navy to find a non-ozone depleting refrigerant for retrofitting the navy’s fleet of 850 shipboard chillers currently using the chlorofluorocarbon R114 as a refrigerant. Describes the findings, which show R236fa or R236ea, as logical replacement candidates for R114.
Improving the efficiency of air conditioning refrigeration Smith. M. H. and Calder. K. Co& ro Examine Cost Effective Solutions. ,, Inst. defrig., 1995, 15 pi. . 96105425
The paper discusses improvements refrigeration.
in the efficiency
of air conditioning
96105426 Indoor air quality and the varlable-alr-volume/bypass filtration system: Chamber experlment Moschandreas, D. J. er al., Environmenf Inr., 1996, 22, (2), 149-158. Two series of experiments were performed in an all aluminum chamber under controlled conditions lo investigate whether the variable-air-volume/bypass filtration system reduces indoor air pollutant concentrations relative to a conventional variable-air-volume. Twelve short-term experiments (100 min) were performed for each ventilation system using indoor sources and one energy load.
The influence of heat-transfer law on the endoCarnot refrigerator Chen, L. er al., J. Iwr. of Energy, Jun. 1996, 69, (479), 96-100. The general performance characteristics of a finite-speed Carnot refrigerator were investigated, and the relationship between the coefficient of per-
96105427
reversible
formance and the cooling load of the refrigerator was obtained for several heat-transfer cases. The results provide a realistic design criterion for actual refrigerators.
96105426 prediction
Measurement and computational fluid dynamics of diffuser pressure-loss coefficient Gan, G. and Riffat, S. B. Applied Enero, Jun. 1996, 54, (2), 181-195. The paper presents measurements and predictions of the pressure-loss coefficient for a wide-angle, three-dimensional diffuser with free discharge. The constant tracer-gis method was used for measuring duct mean vel& ity, and static pressure tappings for pressure change across the diffuser. The effect on the loss coefficient of a bend orecedine the diffuser was investigated for various spacer lengths. Compuiational fluid dynamics predictions were carried out to study flow stabilities in diffusers of different divergence angles.
for improving the operation and energy of HVAC cooling systems Kosonen, R. et al., Finlatrd Technical Research Centre, TRC Research Note 1725, 1996, 82 pp. (In Finnish) 96105429
Murdoch,
M. er al., Refrig. Alr Condit., Feb. 1996, 99, 19-33. Six short articles dealing with aspects of chiller technology applications.
96105424 Identifying and evaluating for navy shlpboard~chillers
Methods
performance
The report presents retrofit concepts primarily addressing the energy efficiency and operation of cooling systems. Considers direct expansion cooling systems, water chillers and room air conditioner packages.
96105430
Moisture
exchange
in rotary
heat
exchangers
Dreher, E. K!‘Lufr. Kalrerech., Jan. 1996, 32, (l), 23-27. (In German) Reports that the achievable heat recovery efficiences of rotary heat recovery units employing a sorptive activated coating, as used in air conditioning systems, are controversial. Discusses a newly designed diagram in which it demonstrates not only the heat balance and moisture balancing taking account of the sorptive material, but also the correlative influence.
96105431 Natural ventilation in atria Andersen, K. T. ASHRAE Trans., Paper NoSD-95-6-4, 1995, 101, (2), 866-874. Discusses how natural ventilation by thermal buoyancy and wind is very suitable for atria, provided the geometry and openings are correctly designed. Presents a set of formulas for determining air velocities, temperature differences and ventilation capacity in relation to openings,
Optimisation functions in building services 96105432 Steinemann, J. Techtrik am Bau, Feb. 1996, (2), 49-52, 69-70. (In German) Describes model calculations for applications in air conditioning and ventilation based on Swiss guidelines.
Optimisation of availability performance in a dissystem Kekkonen, S. Finland Techtrical Research Cenrre, TRC Research Note 1670, 1995, 47pp. (III Finnish) 96105433
trict
heating
Discusses the Finnish
district
heating system.